1. RENO for Neutrino Mixing Angle q13
(“Neutrinos in Cosmology, in Astro-, Particle- and Nuclear Physics”
Sep , 2009, Erice/Sicily, Italy)
Soo-Bong Kim
Seoul National Univ.

2. New Reactor Neutrino q13 Experiment
CHOOZ : Rosc = 1.01 ± 2.8% (stat) ± 2.7% (syst)
→ Obtain ~1% precision !!!
Larger statistics
- More powerful reactors (multi-core)
- Larger detection volume
- Longer exposure
arXiv: v2, Fogli et. al.
Hint of q13 >0 from different data sets and combinations : 1s range
Smaller experimental errors
- Identical multi detectors
Lower background
- Improved detector design
- Increased overburden

3. Detection of Reactor Neutrinos
data from CHOOZ
hep-ex/ v1
(1) 0.7<Eprompot <9MeV
(2) 5<Edelayed <11MeV
(3) 1μs<ΔT <200μs
e+ energy
n capture energy

4. RENO Collaboration (11 institutions and 40 physicists)
Chonnam National University
Dongshin University
Gyeongsang National University
Kyungpook National University
Pusan National University
Sejong University
Seoul National University
Sungkyunkwan University
Seokyeong University
Institute of Nuclear Research RAS (Russia)
Institute of Physical Chemistry and Electrochemistry RAS
(Russia)
+++

5. Comparison of Reactor Neutrino Experiments
Location
Thermal Power
(GW)
Distances
Near/Far
(m)
Depth
(mwe)
Target Mass
(tons)
Double-CHOOZ
France
8.7
280/1050
60/300
10/10
RENO
Korea
17.3
290/1380
120/450
16/16
Daya Bay
China
11.6
360(500)/1985(1613)
260/910
402/80

6. Schematic Setup of RENO at YongGwang

7. Google Satellite View of YongGwang Site

8. Schematic View of Underground Facility
70m high
200m high
1,380m
290m
Far Detector
Near Detector
Reactors

9. RENO Detector 421(354+61) 10” PMTs total ~460 tons Inner Diameter (cm)
Inner Height (cm)
Filled with
Mass (tons)
Target Vessel
280
320
Gd(0.1%) + LS
16.1
Gamma catcher
400
440 LS
28.5
Buffer tank
540
580
Mineral oil
64.4
Veto tank
840
880
water
352.6
421(354+61) 10” PMTs
total ~460 tons

10. Schedule

11. Summary of Construction Status
03~10, 2007 : Geological survey and tunnel design are completed.
07~11, 2008 : Construction of both near and far tunnels are completed.
12, 2008 ~ 03, 2009 : Veto tanks and peripheral facilities (electricity, air circulation, drainage, network, etc.) are completed.
10, 2008 : A mockup detector (~1/10 in volume) was built and is tested out.
11, 2008 : SK new electronics were adopted and ready.
Steel/acrylic containers and mechanical structures are under installation and will be completed until Nov
PMT installation is expected to start from Dec
Both near and far detectors are expected to be ready for data-taking in mid 2010.

12. (2007.3~2007.8) Rock quality map Near detector site:
tunnel length : 110m
overburden
height : 46.1m
Far detector site:
tunnel length : 272m
overburden
height : 168.1m

13. Detectorvertical hall
Design of Tunnels
(2007.9~ )
Wing tunnel(L)
Access tunnel
Experimental hall
Wing tunnel(C)
Detector
Experimental hall
Access tunnel
Wing tunnel(C)
Detectorvertical hall

14. Near & far tunnels are completed
(2008.6~2009.3)
by Daewoo Eng. Co. Korea

15. Detector vertical halls are ready
( ~2009.2)

16. Buffer steel tanks are installed
(2009.6~2009.9)
by NIVAK Co. Korea

17. Acrylic vessels will be ready in Nov. 2009 Bending acrylic plates
(2009.7~ )
by KOATECH Co. Korea
Target
Gamma catcher
Bending acrylic plates
A half of target

18. Mockup Detector ~1/10 of RENO in volume
Target + Gamma Catcher Acrylic Containers
(PMMA: Polymethyl Methacrylate or Plexiglass)
Target
Diameter
61 cm
Height
60 cm
Gamma Catcher
120 cm
Buffer
220 cm
Buffer
Stainless Steel Tank
~1/10 of RENO in volume

19. Mockup Detector Assembly

20. Energy Calibration of Mockup Detector
252Cf
60Co
137Cs
60Co
137Cs

21. Electronics Use SK new electronics (all hardwares are ready)
Conceptual design of the system

22. Gd Loaded Liquid Scintillator Aromatic Solvent & Flour
CnH2n+1-C6H5 (n=10~14)
Recipe of Liquid Scintillator
Aromatic Solvent & Flour
WLS
Gd-compound
LAB
PPO +
Bis-MSB
0.1% Gd+TMHA
(trimethylhexanoic acid)
High Light Yield : not likely Mineral oil(MO)
replace MO and even Pseudocume(PC)
Good transparency (better than PC)
High Flash point : 147oC (PC : 48oC)
Environmentally friendly (PC : toxic)
Components well known (MO : not well known)
Domestically available: Isu Chemical Ltd. (이수화학)
0.1% Gd compounds with CBX (Carboxylic acids; R-COOH)
- CBX : MVA (2-methylvaleric acid), TMHA (trimethylhexanoic acid)

23. RENO Analysis Control
Raw/MC
Data
Production
Modules
Reconstruction
User
Analysis
ntuples
RACFrameWork
default modules data input and output, database access for run configuration and calibration
Has talk-to function for changing input parameters without recompiling
Addition of modules by user
Modules can be set as filter module for selecting events
Easy to use and build in RENO software environment

24. Reconstruction : vertex & energy
Reconstructed vertex:  ~8cm at the center of the detector y
4 MeV (KE) e+
|y|
sy (mm)
Evis (MeV)
Energy response and resolution:
visible energy
PMT coverage, resolution
~210 photoelectrons
per MeV
1 MeV (KE) e+

25. Reconstruction of Cosmic MuonsA B C D
Veto
(OD)
Buffer
(ID)
pulse height
time
OD PMTs
ID PMTs
target
buffer
g-catcher

26. RENO Event Display

27. Calculation of Background Rates due to Radioactivity
Concentration 40K (ppb)
Concentration 232Th (ppb)
Concentration 238U (ppb)
40K [Hz]
232Th [Hz]
238U [Hz]
Total [Hz]
Rock
4.33(ppm)
7.58(ppm)
2.32(ppm)
1.06
7.14
0.99
9.2
LS in Target
0.010
0.018
0.014
9.00
1.63
3.67
14.3
Target Contatiner
0.008
0.207
0.168
0.08
0.24
0.63
1.0
LS in Gamma Catcher
15.18
2.27
5.27
22.7
Gamma Catcher Container
0.07
0.17
0.9
LS in Buffer
0.020
0.005
0.77
0.16
0.14
1.1
Buffer Tank
0.06
0.03
0.10
0.20
0.3
PMT
13.6
208.5
49.4
2.50
5.23
2.99
10.7
Total
~60.2

28. Systematic Uncertainty Goals
Systematic Source
CHOOZ (%)
RENO (%)
Reactor related absolute normalization
Reactor antineutrino flux and cross section
1.9
< 0.1
Reactor power
0.7
0.2
Energy released per fission
0.6
Number of protons in target
H/C ratio
0.8
Target mass
0.3
Detector Efficiency
Positron energy
0.1
Positron geode distance
0.0
Neutron capture (H/Gd ratio)
1.0
Capture energy containment
0.4
Neutron geode distance
Neutron delay
Positron-neutron distance
Neutron multiplicity
0.5
0.05
combined
2.7
< 0.5

29. Expected Number of Neutrino Events at RENO
2.73 GW per reactor ⅹ 6 reactors
1.21x1030 free protons per targets (16 tons)
Near : 1,280/day, 468,000/year
Far : /day, ,600/year
3 years of data taking with 70% efficiency
Near : 9.83x105 ≈ (0.1% error)
Far : x104 ≈ (0.3% error)

30. RENO Expected Sensitivity
90% CL Limits
Discovery Potential” (3s)

31. RENO Expected Sensitivity
New!! (full analysis)
10x better sensitivity than current limit

32. GLoBES group workshop@Heidelberg – Mention’s talk
SK Dm2

33. Status Report of RENO
RENO is suitable for measuring q13 (sin2(2q13) > 0.02)
Geological survey and design of access tunnels & detector cavities are completed → Civil construction was finished in February, 2009.
Buffer steel containers are installed.
RENO is under installation phase.
Data –taking is expected to start in mid 2010.
International collaborators are being invited.